Eukaryotic initiation factor 4 A (eIF4A) plays critical roles during translation initiation of cellular mRNAs by forming the cap-binding eIF4F complex, recruiting the 40S small ribosome subunit, and scanning the 5' untranslated region (5' UTR) for the start codon. eIF4A1 and eIF4A2, two isoforms of eIF4A, are highly conserved and exchange freely within eIF4F complexes. The understanding of their biological and molecular functions remains incomplete if not fragmentary. In this study, we showed that eIF4A1 and eIF4A2 exhibit different expression patterns during B-cell development and activation. Mouse genetic analyses showed that they play critical but differential roles during B-cell development and humoral immune responses. While eIF4A1 controls global protein synthesis, eIF4A2 regulates the biogenesis of 18S ribosomal RNA and the 40S ribosome subunit. This study demonstrates the distinct cellular and molecular functions of eIF4A1 and eIF4A2 and reveals a new role of eIF4A2 in controlling 40S ribosome biogenesis.
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http://dx.doi.org/10.1038/s41423-024-01234-x | DOI Listing |
Cell Mol Immunol
January 2025
State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian, 361102, China.
Eukaryotic initiation factor 4 A (eIF4A) plays critical roles during translation initiation of cellular mRNAs by forming the cap-binding eIF4F complex, recruiting the 40S small ribosome subunit, and scanning the 5' untranslated region (5' UTR) for the start codon. eIF4A1 and eIF4A2, two isoforms of eIF4A, are highly conserved and exchange freely within eIF4F complexes. The understanding of their biological and molecular functions remains incomplete if not fragmentary.
View Article and Find Full Text PDFInhibition of translation initiation using eIF4A inhibitors like (-)-didesmethylrocaglamide [(-)-DDR] and (-)-rocaglamide [(-)-Roc] is a potential cancer treatment strategy as they simultaneously diminish multiple oncogenic drivers. We showed that human and dog osteosarcoma cells expressed high levels of eIF4A1/2, particularly eIF4A2. Genetic depletion of eIF4A1 and/or 2 slowed osteosarcoma cell growth.
View Article and Find Full Text PDFLife Sci Alliance
February 2024
Immunology Programme, The Babraham Institute, Babraham Research Campus, Cambridge, UK
Clin Proteomics
November 2023
Department of Medical Oncology, Cancer Center Amsterdam, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
The tyrosine kinase inhibitor sunitinib is an effective first-line treatment for patients with advanced renal cell carcinoma (RCC). Hypothesizing that a functional read-out by mass spectrometry-based (phospho, p-)proteomics will identify predictive biomarkers for treatment outcome of sunitinib, tumor tissues of 26 RCC patients were analyzed. Eight patients had primary resistant (RES) and 18 sensitive (SENS) RCC.
View Article and Find Full Text PDFRNA
June 2023
Department of Biochemistry, McGill University, Quebec, H3G 1Y6 Canada
Inhibition of eukaryotic translation initiation through unscheduled RNA clamping of the DEAD-box (DDX) RNA helicases eIF4A1 and eIF4A2 has been documented for pateamine A (PatA) and rocaglates-two structurally different classes of compounds that share overlapping binding sites on eIF4A. Clamping of eIF4A to RNA causes steric blocks that interfere with ribosome binding and scanning, rationalizing the potency of these molecules since not all eIF4A molecules need to be engaged to elicit a biological effect. In addition to targeting translation, PatA and analogs have also been shown to target the eIF4A homolog, eIF4A3-a helicase necessary for exon junction complex (EJC) formation.
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